Efficient algorithm to find all the paths from A to Z?

Question

With a set of random inputs like this (20k lines):

A B
U Z
B A
A C
Z A
K Z
A Q
D A
U K
P U
U P
B Y
Y R
Y U
C R
R Q
A D
Q Z

Find all the pat

Answer 1

Your data is essentially an adjacency list which allows you to construct a tree rooted at the node corresponding to A. In order to obtain all the paths between A & Z, you can run any tree traversal algorithm.

Of course, when you're building the tree you have to ensure that you don't introduce cycles.